This invention relates to disposable diapers. More particularly, this invention relates to disposable diapers adapted to be secured in place by adhesive tabs.
Disposable diapers provide substantial advantages in convenience over diapers intended to be laundered and reused, particularly when they are used away from home. In recent years, many different disposable diapers have been proposed and some have been successful in the marketplace. Typical disposable diaper structures comprise a moisture-retaining layer of high liquid-holding capacity and a moisture-impervious backing sheet therefor, generally made of a plastic film such as polyethylene film or the like. Typical disposable diaper structures are shown in U.S. Pat. No. 3,612,055 to Mesek et al. and in U.S. Pat. No. Re. 26,151 to Duncan et al.
As may be seen from the above-cited patents, it is desirable to obviate the problems that are inherent in closure systems which utilize extraneous fasteners such as safety pins, snaps and zippers. To this end adhesive closure systems have presented acceptable solutions which eliminate the need for pins, for example, which present problems especially when the infant is active during the diaper changing.
Although tape tab fastening means have become a suitable substitute for extraneous fasteners such as pins, a suitable tape tab fastening system has not been developed to simulate the ability of an extraneous fastener to be opened and subsequently closed. For example, when using pin fastening, if a diaper needs checking to see if the diaper has been soiled, the pin permits opening, and if no soiling is evident, the diaper is again closed about the infant by repinning. Most prior tape tab systems have not provided this flexibility. The commercially available tape tabs which are used on disposable diapers cannot be disengaged readily to check for soiling or for repositioning the diaper. On most, if not all, occasions undesirable rupture of the outside sheet of the diaper occurs, or the tape tab itself is torn in checking the diaper. This tearing has made refastening unmanageable or impossible and frequently results in the loss of a possibly unsoiled diaper.
In an attempt to solve the foregoing problems, U.S. Pat. No. 3,848,596 to Pennau teaches a tape tab fastening means which allows an originally fastened diaper to be opened and subsequently closed. The tape tab consists of two adhesive areas on each tab covered by two release sheets. On the first closure, only one release sheet is removed to expose pressure-sensitive adhesive. Upon adjustment or inspection, the tape is peeled from the fastened position, or the tab torn, and the other release sheet is removed, exposing fresh adhesive for a subsequent fastening. This arrangement is practical for only two fastenings, the original and one more and has the serious drawback that undesirable rupture of the diaper can occur when peeling off the tape tab if the diaper user does not choose to tear the tab itself. With a torn fastening area, refastening is very difficult even with a freshly exposed adhesive area on the tape.
U.S. Pat. No. 3,616,114 to Hamaguchi et al. discloses an adhesive sealing tape which can be used for releasably interconnecting parts of a diaper or other container. The fixed end of a main tape portion is attached to one side of a first container part. A reinforcing tape portion is provided with a turned up end which is attached to the undersurface of the midregion of the main tape portion, and a part of the reinforcing tape portion is attached to the opposite side of the first container part. The free end of the main tape portion is adapted for attachment to a second container part which is to be secured to the first container part. Thus, the Hamaguchi et al. patent requires two interconnected tape portions which cause the folded configuration of the sealing tape to be somewhat bulky.
One of the embodiments disclosed in U.S. Pat. No. 2,932,747 to Dexter is a fastener having two overlapping gummed strips adhesively bonded together. The overlapping strip is attached to one fabric and the underlying strip is attached to another fabric. The adhesive bond between the two strips is the weakest link in the chain of attachment so that when the fastener is placed under stress, failure will occur between the two gummed strips before damaging loads can develop in the fabric. The adhesive on the overlapping strip terminates short of one end thereof to provide an unattached portion of the overlapping strips which can be grasped and peeled away from the underlying strip to sever the fabric joint.